Originally posted by: BlurredLines
 
This was the concept from one of the recent survivor season in America , they introduced it in season 38 out of their 41 season , so bit new but I will try to explain as much as I am aware. 
The contestants who got eliminated will live together in third world , unlike duels which happened so far, there will be only one round that will decide who will reenter. For example if in tje following weeks Nanda, Amazad, Naryanan, Vanessa all gets eliminated . All of them will fight together for a chance to renter in to the game and only one of them who win will enter. 
As far advantages , it is usually some knowledge about the one round they might compete in or some sort of advantage for the contestant . 
In Edge of extinction one person got a advantage that allowed them to practice a part of their challenge before the round, another person got a advantage that allowed them to choose one of their opponents and make them start few seconds later than the rest and he choose the tough competitior among them for it . 
So the advantage will be related to the one round they might have to compete to get back on the game . 
Because Saran lost today challenge , he will have no advantage for that round , Aishwarya will have one advantage for winning this challenge I guess and she will get to compete with the next week eliminated contestant to get one more advantage I suppose , if she loses then she will not get a chance to more advantage and the person who beat her will be able to fight for the advantage I guess. 
In Edge of Extinction, there were no challenge but just clues to where the advantage are hidden in the island and the contestant who cracks it and finds it gets to keep it , so I am not that sure how they are doing it in Tamil so far.